macronucleus
Sign in to saveAlso known as meganucleus
A macronucleus (formerly also meganucleus) is the larger type of nucleus in ciliates. Macronuclei are polyploid and undergo direct division without mitosis. It controls the non-reproductive cell functions, such as metabolism. During conjugation, the macronucleus disintegrates, and a new one is formed by karyogamy of the micronuclei.
Research
1,322 papers- Evolution of amitosis of the ciliate macronucleus: gain of the capacity to divide.The Journal of protozoology · 1991
- Origin, structure and function of millions of chromosomes present in the macronucleus of unicellular eukaryotic ciliate, Oxytricha trifallax: a model organism for transgenerationally programmed genome rearrangements.Journal of genetics · 2015
- The Ciliary Protein IFT57 in the Macronucleus of Paramecium.The Journal of eukaryotic microbiology · 2018
- Rearrangement of macronucleus chromosomes correspond to TAD-like structures of micronucleus chromosomes in Tetrahymena thermophila.Genome research · 2020
- Macronucleus structure and macronucleus development in hypotrichous ciliates.The International journal of developmental biology · 1996
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Encyclopedic overview
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A macronucleus (formerly also meganucleus) is the larger type of nucleus in ciliates. Macronuclei are polyploid and undergo direct division without mitosis. It controls the non-reproductive cell functions, such as metabolism. During conjugation, the macronucleus disintegrates, and a new one is formed by karyogamy of the micronuclei.
Macronuclei contain hundreds to thousands of chromosomes, each present in many copies. There is no mechanism to precisely partition this complex genome equally during nuclear division; thus, how the cell manages to maintain a balanced genome after generations of divisions is unknown.
Excerpted from Wikipedia’s “macronucleus” article, available under the CC BY-SA 4.0 licence.